Quantum dots (QDs) CdSe exhibits relatively high photocatalytic abilities for its unique properties, but the aggregation and photocorrosion have blocked its further application. Therefore, for arriving at a solution, alkaline earth metal ions (M= Mg2+, Ca2+, Sr2+ and Ba2+) and reduced graphene oxide (rGO) are chosen to fabricated new QDs CdSe-based photocatalytic systems. In this paper, M@CdSe/rGO composites have been synthesized via a facile one-step hydrothermal approach, during which the formation of M doped CdSe crystallization and GO reduction occur simultaneously. The obtained Photocatalysts demonstrates synergistically enhanced visible light photocatalytic activity and stability toward photodegrading tetracycline hydrochloride (TC-HCl) solution, especially the introduction of 6 mol% Ca2+ and 5 wa GO on QDs CdSe resulted in 85.6% degradation of 15 mg/L TC-HCl in 1 h with 0.5 g/L catalyst. Furthermore, the photodegradation mechanism was systematically investigated by active species trapping experiment. It revealed that h(+) was the major active species in the destructions process. And the possible process of charge transfer for Ca2+@CdSe/rGO nanocomposite was proposed based on the experimental results. (C) 2015 Elsevier B.V. All rights reserved.